Stem cell technique offers new potential to treat blindness

UCL scientists are
pioneering a stem cell treatment to replace diseased parts of the retina, which
could lead to a future treatment for retinal diseases that affect around 3,000
children in the UK.

The researchers from UCL Institute of Child Health and UCL
Institute of Ophthalmology, also members of the UCL Centre for Stem Cells and Regenerative Medicine, successfully implanted cells from healthy mice into
mice with an inherited form of childhood blindness called Leber Congenital Amaurosis (LCA).

The implanted cells express a gene called
Crx which is needed to make healthy cone and rod photoreceptors. The cells were able to integrate with the retina and become
new cone photoreceptors. This is the first time this has been achieved. Further
studies are needed to demonstrate whether it is possible to restore sight using
this method.

Dr Jane Sowden from the UCL Institute of Child Health, who
led the study, said: “We have shown for the first time that it is possible to
transplant new cone photoreceptors into the mature retina. The newly-developed cones looked as good as new. This is an
important step forward as cone photoreceptors are essential for reading vision
and for colour vision and loss of this type of cell has the biggest impact on
sight.

“It may be possible to translate this success into
treatments for humans. Recent research has shown that embryonic stem cells
capable of self-renewal could provide an equivalent source of human cells that
express the Crx ‘photoreceptor-creating’ gene and could be grown in the lab
before being transplanted in the retina.”

Professor Robin Ali from UCL Institute of Ophthalmology, who
co-led the study, said: “We are now working to assess how much vision can be
improved by photoreceptor cell transplantation and how effectively they can
replace degenerating cells at different stages of disease. There is still a lot
more basic research that needs to be carried out, but this is a very promising
area that we hope will translate into a future treatment for patients who
cannot see because their photoreceptors have degenerated.”

One
in 3,000 people are affected by incurable genetically inherited retinal
disease. LCA is the most severe form that causes blindness from birth or during the first few months of life and
affects around 200,000 children worldwide. These diseases cause the light sensitive
photoreceptor cells in the retina to die,
leading to loss of sight.

‘Cone
and rod photoreceptor transplantation in models of the childhood retinopathy
Leber congenital amaurosis using flow-sorted Crx-positive donor cells’
is published in Human Molecular Genetics
today. The research was funded by the MRC, the Macula Vision Research
Foundation and Fight for Sight.

UCL context

The UCL Centre for Stem Cells and Regenerative Medicine brings together 169 research groups from
several faculties, hospitals and institutes across UCL with a common interest in all aspects of
stem
cells, tissue engineering, repair and regeneration and the development
of their
therapeutic and biotechnological potential

Moorfields Eye Hospital, Great Ormond Street Hospital for Children,
UCLH, the Royal Free and UCL together form UCL Partners, Europe’s largest
academic health science partnership.